Use SkImageCacherator in SkImages

include/gpu/SkGr.h

Index: include/gpu/SkGr.h
diff --git a/include/gpu/SkGr.h b/include/gpu/SkGr.h
index e0f8b402db2de9fc9bd765dc7237e2cd8325f63e..68b93a1f8a7e15fcc775c95ead7016325d0ae59c 100644
--- a/include/gpu/SkGr.h
+++ b/include/gpu/SkGr.h
@@ -81,7 +81,10 @@ GrPixelConfig GrIsCompressedTextureDataSupported(GrContext* ctx, SkData* data,
                                                  int expectedW, int expectedH,
                                                  const void** outStartOfDataToUpload);
 
+// Helper that calls GrIsImageInCache assuming bitmap is not volatile.
 bool GrIsBitmapInCache(const GrContext*, const SkBitmap&, const GrTextureParams*);
+bool GrIsImageInCache(const GrContext* ctx, uint32_t imageID, const SkIRect& subset,
+                      GrTexture* nativeTexture, const GrTextureParams*);
 
 GrTexture* GrRefCachedBitmapTexture(GrContext*, const SkBitmap&, const GrTextureParams*);
 GrTexture* GrRefCachedBitmapTexture(GrContext*, const SkBitmap&, SkImageUsageType);